//
// Created by Jisam on 2024/7/23.
//
#include <bits/stdc++.h>

#define PSI pair<string,int>
#define PII pair<int,int>
#define VVI vector<vector<int>>
#define VI vector<int>
#define VS vector<string>

#define PQLI priority_queue<int, vector<int>, less<int>>
#define PQGI priority_queue<int, vector<int>, greater<int>>
#define i64 long long

using namespace std;

const int N = 1e5 + 5;
i64 ans;

void solve() {
    int n, k;
    string a;
    cin >> n >> k >> a;
    bool ok,flag;
    sort(a.begin(),a.end());
    while(true){
        ok=true;
        for(int i=0;i<=n-k;i++){
            flag=true;
            for(int j=0;j<k;j++){
                if(a[i+j]!=a[i+k-1-j])flag=false;
            }
            if(flag)ok=false;
        }
        if(ok)ans++;
        if(!next_permutation(a.begin(), a.end()))break;
    }

    cout<<ans<<endl;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int T = 1;
//    cin >> T;
    while (T--) solve();
//    cout << "\n"[];
    return 0;
}